Wearing gloves, wash and dry the jalapenos. Cut the stems off and slice into ¼” thick rounds.
In a medium pot, combine the vinegar, sugar, and all the spices. Heat over medium, stirring until all the sugar is dissolved.
Add the sliced jalapenos and return to the heat, cooking for 12-15 minutes until the jalapenos are soft and have started to absorb the sugar.
Strain the jalapenos into the prepared, clean glass jar using a slotted spoon, leaving the liquid in the pot. With a fine mesh strainer, remove most of seasonings if desired.
Return the liquid to medium heat. Cook for a further 7-10 minutes at a boil until the liquid has reduced by half and is a very thick syrup.
Pour the syrup over the jalapenos and place the lid on. Allow to cool before eating. Store in the fridge for up to 2 weeks.